Building material products containing organic polymers as thickeners

ABSTRACT

Building material products, such as, for example, jointing compounds, adhesives, emulsion paints, synthetic plasters, fillers and the like, comprising a mixture of 
     a) at least 10% by weight, in particular 10 to 99% by weight, of a water-soluble natural polymer and derivatives thereof, 
     b) 1 to 89% by weight of an alkali metal salt or ammonium salt of a crosslinked polyacrylate which, if desired, is grafted with a starch, and 
     c) 0 to 60% by weight of a water-soluble alkali metal salt or alkaline earth metal salt of arylsulfonic acid/formaldehyde condensation products or of a sulfo-modified melamine/formaldehyde polycondensation product.

It is known that derivatives of natural polymers, such as cellulose ethers, xanthan gums, guar derivatives are capable of increasing the viscosity in aqueous media to a substantial degree as a function of their chain length and concentration. The physical effects linked thereto make it possible to utilize these substances as thickeners, water-retention agents, protective colloids, dispersants, stabilizers and binders in a large number of industrial applications. The variety of properties of these polymers enables their complex use in a wide range of different industrial and product sectors. These include building materials, paints, adhesives, detergents and cleaning compositions, cosmetics, foodstuffs, pharmaceuticals, products of the textile, leather, paper, and ceramics industries.

The crucial and most important characteristic of the polymers is their viscosity in aqueous solution under specific conditions (concentrations, temperature, measuring device, shear gradient). For many applications, polymers are required which, when dissolved in water, give high viscosities, as a result of which a high thickening effect and water retention but also a significant improvement in stability can be achieved, ideally at relatively low concentrations of the polymers.

Many measures aim at increasing the viscosity-increasing effect of the polymers and raising their economy and efficiency. Particularly careful selection of the starting raw materials (in the case of cellulose ethers: high-quality chemical pulps or cotton linters), in combination with chemical reactions avoiding excessive chain degradation (for example etherification) and particular measures for gentle drying and fine grinding are the prerequisite for maintaining a high degree of polymerization and preparing highly viscous macromolecular substances. Moreover, the chain length of the polymers can be lengthened by suitable chemical reactions, for example by crosslinking reactions with dichlorinated aromatics or olefins.

For example, in the case of cellulose ethers the measures and developments mentioned lead to viscosity ranges (measured as a 2% aqueous solution) of more than 100,0000 mPa.s, in exceptional cases of up to 400,000 mPa.s. Despite fine grinding under gentle conditions to give usable powdered products, nevertheless, chain degradation of the polymers, which in some cases can be significant, and which necessarily leads to reduced viscosities takes place. This involves economic disadvantages, since high-quality raw materials are expensive and a complicated process resulting in reduced yield is necessary for the preparation.

Furthermore, it is known that polyacrylates are used in the form of their alkali metal salts and ammonium salts as valuable thickeners for controlling the rheology of aqueous systems, for example in emulsion paints, paste-like fillers and adhesives. A special group are the crosslinked polyacrylates or polyacrylates which are crosslinked and additionally grafted with starch, which are increasingly being used as so-called superabsorbents (SAPs) in hygiene articles (diapers, sanitary napkins), in agriculture and in horticulture, in the transport of sensitive foodstuffs, in pharmaceutics, cosmetics, internal construction, as sludge solidifier and for sealing landfills.

The capacity of these polymers to absorb large volumes of aqueous liquids with the formation of a stable gel structure and even to withstand stress is the prerequisite for their successful use in the areas described above. It is true that experimental applications of SAPs in the areas of building materials, paints and adhesives show a thickening effect, which in some cases is clearly noticeable, despite their distinct properties to absorb extraordinarily high amounts of aqueous liquids (up to 400 to 1000 times their own weight), but they do not even come close to reaching the high water retention capacity of natural polymers (such as, for example, of cellulose ethers) which is also necessary for the above-mentioned systems.

Furthermore, it is known that alkali metal salts and alkaline earth metal salts of the condensation products of arylsulfonic acids, i.e. of phenolsulfonic acids and naphthalenesulfonic acids, are used together with formaldehyde as stabilization aid, dispersants, plasticizing agents and liquefying agents in various branches of industry. The condensation products mentioned are of particular importance as plasticizing and liquefying agents in concrete and mortar production in the building industry.

The high dispersability and liquefying effect lead in mortar and concrete, especially where a large amount is metered in, to extensive deposition of a water/binder slurry, as a result of which the initially present good plasticity and processability is substantially lost upon storage of the mortar or concrete, due to high internal compression.

A simple and low-cost method is desired which significantly increases the viscosity ranges of the natural high polymers in aqueous media and thus substantially improves the thickening effect.

Surprisingly, it has now been found that by using combinations of water-soluble natural polymers or derivatives thereof, such as cellulose ethers, xanthan gums, guar derivatives, starch ethers, carobseed flour with alkali metal salts and ammonium salts of crosslinked and optionally additionally starch-grafted polyacrylate superabsorbents, and, if desired, with additions of alkali metal salts and alkaline earth metal salts of condensation products of naphthalenesulfonic acid or phenolsulfonic acid with formaldehyde or with sulfo-modified melamine/formaldehyde polycondensation products, viscosity ranges in aqueous media can be achieved which are significantly higher than those of the starting substances mentioned. Combinations of the natural polymers mentioned or derivatives thereof with superabsorbents alone produce a significant increase in the viscosity ranges compared with those of the starting substances used.

The invention relates to building material products comprising a mixture of

a) at least 10% by weight, in particular 10 to 99% by weight, preferably 40 to 90% by weight, of a water-soluble natural polymer and derivatives thereof,

b) 1 to 89% by weight, preferably 5 to 60% by weight, of an alkali metal salt or ammonium salt of a crosslinked polyacrylate which, if desired, is additionally grafted with a starch, and

c) 0 to 60% by weight, preferably 1 to 40% by weight, of a water-soluble alkali metal salt or alkaline earth metal salt of arylsulfonic acid/formaldehyde condensation products or of a sulfo-modified melamine/formaldehyde polycondensation product.

The term "building material products" is here and hereinafter understood to mean fillers, adhesives, emulsion paints, synthetic plasters, jointing compositions and other products of this type.

In order to increase the viscosity, these products contain a mixture of the abovementioned components a) to c) in the composition given. These components will be described below in more detail.

a) water-soluble natural polymers and derivatives thereof

Preferred examples of these are the following products:

    ______________________________________                                         1. Cellulose ethers                                                            The viscosity limits of these cellulose ethers are usually                     10-500,000, in particular 50-150,000, mPa · s (measured as a 2%       aqueous solution using a Hoppler falling-ball viscometer at 20°         C.                                                                             in distilled water). The most important cellulose ethers in                    practical application have the following etherification data:                                        DS               MS                                      Methylcellulose       1.4-2.3                                                  Methylhydroxyethyl-   1.3-2.0          0.05-0.5                                cellulose                                                                      Methylhydroxypropyl-  1.3-2.2          0.1-1.0                                 cellulose                                                                      Hydroxyethylcellulose --               1.8-3.5                                 Hydroxyethylhydroxy-            MS HE: 0.9-1.2                                 propylcellulose                 MS HP: 0.6-0.9                                 Hydroxypropylcellulose                                                                               --               2-3.5                                   Ethylhydroxyethyl-    0.7-1.2          0.8-2.7                                 cellulose                                                                      Carboxymethylcellulose                                                                               0.5-1.5          --                                      Carboxymethylhydroxy- 0.3-0.6          0.3-2.3                                 ethylcellulose                                                                 Alkoxyhydroxypropyl-  --               1.5-3.5                                 hydroxyethylcellulose                                                          Alkoxy group:                                                                  straight-chain or branched, 2-8 carbon atoms, 0.05-50%, relative               to the weight of the substituted cellulose ether                               Carboxymethylated                                                                                    DS OCH.sub.3     MS                                      methyl-                                                                        hydroxyethyl- or      1.3-2.0          0.05-0.5                                methylhydroxypropyl-  1.3-2.2          0.1-1.0                                 cellulose                                                                      2. Starch ethers                                                               Hydroxypropylstarch:                                                                          MS     0.1-0.8                                                  Carboxymethylstarch:                                                                          DS     0.1-0.8                                                  Hydroxypropylcarboxy-                                                                         DS     0.1-0.5/MS 0.1-0.8                                       methylstarch:                                                                  Viscosity limits:                                                                             1-10,000 mPa · s (2% aqueous                                          solution) measured using a Hoppler                                             viscometer at 20° C. and in distilled                                   water                                                           3. Guar gum derivatives                                                        Guar endosperm flour 100-20,000 mPa · s                               (natural galactomannan)                                                        Viscosity (1% in water):                                                       (measured using a Brookfield RVT,                                              25° C. 20 rpm)                                                          Carboxymethylguar    100-20,000 mPa · s                               Viscosity (3% in water):                                                       Hydroxypropylguar    100-10,000 mPa · s                               Viscosity (1% in water):                                                       Carboxymethylhydroxy-                                                                               100-20,000 mPa · s                               propylguar                                                                     Viscosity (1% in water):                                                       Cationized guar      100-20,000 mPa · s                               (quaternary substitution                                                       DS about 0.13)                                                                 Viscosity (1% in water):                                                       4. Xanthan gum       100-10,000 mPa · s                               (Polysaccharides, anionic,                                                     prepared by fermentation                                                       and extraction of                                                              Xanthomonas campestris)                                                        Viscosity (1% in water):                                                       5. Carobseed flour                                                             6. Alginates                                                                   b) Superabsorbents (SAPs)                                                      Superabsorbents are lattice structures based on neutralized                    polyacrylic acid formed in free-radical copolymerization of                    monomers in the presence of small amounts of certain crosslinking              agents. Functionality and reactivity of the crosslinking agents is             of great importance for the properties of a superabsorbent.                    ______________________________________                                    

There are 2 main principles for preparing a polymer lattice structure:

a) the lattice (lattice structure) is synthesized in a single polymerization step, starting with the monomers, for which certain crosslinking agents are required for branching and formation of the lattice structure.

b) A previously synthesized straight-chain or branched polymer is crosslinked.

For the preparation of SAPs, the method mentioned under a) has by far the greatest importance; for specific products, method b) is used. Various techniques are used for the polymerization process (for example emulsion polymerization and gel polymerization). In this process, an aqueous solution of the monomer acrylic acid is polymerized in the presence of small amounts of a crosslinking agent (polyfunctional monomer). Water serves as diluent and solvent (exothermic process) so as to avoid high temperatures. Polymerization can be carried out in a reactor or by means of the thin-film process; concentrations of up to 60% are customary.

The superabsorbents can also be grafted with starch. This grafting with starch is carried out during the polymerization and crosslinking process in a one-pot process. This starch is heated in water to dissolve it and is added as a solution at the beginning of the polymerization process. The proportion of starch, relative to the SAP, can be 3-30% by weight.

Superabsorbents can only absorb in the pH range from 4 to 10; (partial) neutralization can be carried out before or after polymerization. The product formed by polymerization is a moist gel, which is comminuted using a gel cutter and then dried.

Crosslinking for preparing SAPs substantially takes place via covalent bonds, i.e. by using polyfunctional monomers during polymerization (crosslinking agent containing double bonds).

Further crosslinking possibilities via covalent bonds are provided by polyfunctional molecules (diepoxides, azirines, polyalcohols). Already present, slightly crosslinked polymer chains are additionally crosslinked on the surface by means of the crosslinking agents mentioned.

This makes it possible to combine the good absorption properties of the slightly crosslinked superabsorbents (which have high absorption capacity but also large amounts of extractable material and a low absorption ratio, due to gel blocking) with the advantages of highly crosslinked SAPs (no gel blocking, better absorption capacity and absorption stability under compressive stress).

Important crosslinking reagents for the preparation of SAPs are

a) methylenebisacrylamide; a crosslinking agent having high reactivity but leading to SAPs of less resistance to compression;

b) diethylene glycol dialkyl ether; a crosslinking agent having less reactivity, which makes it possible to prepare SAP gels having better elastic properties and higher stability under compressive stress;

c) vinyl compounds (vinyl ethers, vinyl esters, vinyl-phosphonic acid).

In order to achieve an optimum crosslinking and lattice structure of the SAPs, mixtures of crosslinking reagents of high and low reactivity are used in the preparation process, it being possible to modify the density and constitution of the lattice structures over a wide range and adjust them as required by varying the mixing ratios of the crosslinking components used accordingly.

Suitable components c) are:

1. Polycondensation products of naphthalenesulfonic acid with formaldehyde in the form of their alkali metal salts, ammonium salts and alkaline earth metal salts;

Sulfo-modified melamine/formaldehyde polycondensation products in the form of their alkali metal salts or ammonium salts.

The pulverulent and granulated components a), b) and if desired, c) can be individually admixed to the building material products or first components a), b) and c) are mixed by themselves, and this mixture is then added to the building material products. Incorporation of these components in the building material products takes place by conventional stirring and mixing processes, for example by kneading. The sum of components a), b) and c) in the building material products is 0.01 to 2, preferably 0.1 to 0.5, % by weight, relative to the dry composition.

Components a), b) and c) can also be mixed with one another during their preparation, for example by thorough mixing or kneading before or after the drying process during preparation of the respective components. A subsequent joined fine milling produces particularly homogeneous and rapidly acting thickening systems. For combinations obtained by simply mixing the components, superabsorbents having a particle fineness of <0.1 mm have proven to be particularly suitable.

The mixtures described have a strong thickening effect in aqueous medium. In addition, depending on the particular composition of these mixtures, some of them exhibit marked pseudoplasticity, which is mediated to liquidic/pasty systems and causes therein a remarkable structuring effect. The mixtures described are therefore particularly suitable as additives for building material products. These include paste-like tile adhesives, fillers and jointing compounds (in powder form or paste-like, in combination with plastic dispersions, polyvinyl alcohols, animal glue, casein as organic binder), jointing compounds based on polyacrylate and made elastic or plastic, plastic emulsion paints.

This improvement in the structural properties in combination with an increased thickening effect caused by the combinations described makes it possible to omit completely or in part previously required mineral thickening and structuring aids, such as, for example, bentonites, attapulgites, highly disperse silicas. The substantial disadvantage of these inorganic thickeners, i.e. the strong increase in shrinkage behavior before and after hardening or drying of building material systems prepared therewith, can be reduced to a large extent or eliminated by the combinations described. Moreover, they lead to a reduction in costs as a result of reduced amounts used of the combinations compared with the customary amounts of natural polymers added. The claimed combinations moreover improve the processability and smoothness of liquidic pasty systems. The tackiness of building material products containing highly viscous cellulose ethers as thickeners and water retention agents, which is often troublesome, is significantly reduced by using the combinations mentioned. In mineral-based building material systems too, additions of the claimed combinations have a positive effect on processability. The resulting reduced tackiness enables the mortar and plastic compositions to be smoothened more easily. These properties also have an advantageous effect in concrete mixtures (underwater concrete, gunned concrete, pumped concrete), whose homogeneity, stability and pumpability are improved.

Examples:

For the mixtures described below, the following individual components were used:

    __________________________________________________________________________                    Viscosity level                                                                measured in                                                                    2% aqueous                                                                             Degree of etherification                                               solution                                                                               DS      MS                                              __________________________________________________________________________     Methylhydroxyethyl-                                                                           30,000  1.5     0.12                                            cellulose (1)                                                                  Methylhydroxyethyl-                                                                           50,000  1.5     0.11                                            cellulose (2)                                                                  Methylhydroxyethyl-                                                                            6,000  1.5     0.13                                            cellulose (3)                                                                  Methylhydroxyethyl-                                                                            6,000  1.5     0.10                                            cellulose (4)                                                                  Methylhydroxyethyl-                                                                           15,000  1.8     0.12                                            cellulose (5)                                                                  Methylhydroxyethyl-                                                                            6,000  1.6     0.15                                            cellulose (6)                                                                  Methylhydroxyethyl-                                                                           30,000  1.55    0.21                                            cellulose (7)                                                                  Methylhydroxyethyl-                                                                            6,000  1.64    0.24                                            cellulose (8)                                                                  Methylhydroxyethyl-                                                                            4,000  1.88    0.21                                            cellulose (9)                                                                  Hydroxyethylcellulose                                                                          6,000  --      2.1                                             Carboxymethylhydroxy-                                                                          3,000  0.55    0.75                                            ethylcellulose                                                                 Ethylhydroxyethylcellulose                                                                     1,000  0.97    1.9                                             Methylhydroxypropyl-                                                                           4,000  1.88    0.21                                            cellulose                                                                      Alkoxyhydroxypropylhydroxy-                                                                   25,000  DS = OC.sub.3 H.sub.5 (OH)--OC.sub.4 H.sub.9 0.05       ethylcellulose         MS = OC.sub.2 H.sub.4 2.45                              Alkoxyhydroxypropylhydroxy-                                                                   25,000  DS = OC.sub.3 H.sub.5 (OH)--OC.sub.4 H.sub.9 0.08       ethylcellulose         MS = OC.sub.2 H.sub. 4 3.40                             Hydropropylstarch                                                                              1,300  --      0.64                                            (crosslinked with                                                                             (5% aqueous                                                     epichlorohydrin)                                                                              solution)                                                       Guar gum (Mepro guar                                                                           5,000  --      --                                              CSA 200/50)    (1% solution)                                                   Hydroxypropylguam                                                                              4,000  --      0.42                                            (Jaguar ® 8060)                                                                           (1% solution)                                                   Carboxymethylhydroxy-                                                                          3,800  0.06    0.40                                            propylguam     (1% solution)                                                   (Jaguar ® 8600)                                                            Guar gum, quaternary-                                                                          2,000  degree of quaternary                                    substituted (Meyprofloc 130)                                                                  (1% solution)                                                                          substitution = 0.13                                     Xanthan gum    starting                                                        (Rhodopol ® 50 MD)                                                                        viscosity:                                                                     6300 mPa · s                                                          (2% solution)                                                   __________________________________________________________________________                                 Absorption                                                               Centri-                                                                              capacity                                                     Overall absorption                                                                         fuging                                                                               under Extract-                                               capacity in retention                                                                            pressure                                                                             able                                                   deionized                                                                            0.9% NaCl                                                                            0.9% NaCl                                                                            0.9% NaCl                                                                            material                                               H.sub.2 O (g/g)                                                                      sol. (g/g)                                                                           sol. (g/g)                                                                           sol. (ml/g)                                                                          (%)                                          __________________________________________________________________________     Superabsorbent (1)                                                                       500   50    32    15    7                                            SANWET ®                                                                   IM 1500                                                                        (Starch-grafted                                                                sodium polyacrylate) - Superabsorbent (2)                                                1000  65    42     5    14                                           SANWET ®                                                                   IM 1000                                                                        (Starch-grafted                                                                sodium polyacrylate) - Superabsorbent (3)                                                400   48    32    32    3                                            SANWET ®                                                                   IM 5000s                                                                       (Starch-grafted                                                                sodium polyacrylate)                                                           __________________________________________________________________________     Sodium salt:                                                                   Properties        Typical data                                                 __________________________________________________________________________     Naphthalenesulfonic acid/formaldehyde condensation product;                    Supplied          in liquid/pulverulent form                                   Concentration (active content)                                                                   20-40%/70-96%                                                sodium sulfate content                                                                           0-25%                                                        Molecular weight  4,000-40,000                                                 pH                6.5-11                                                       Viscosity (23° C.)                                                                        10-150 mPa · s liquid products)                     Melamine/formaldehyde condensation product, sulfonated;                        Supplied          in liquid/pulverulent form, granules                         Concentration (active content)                                                                   about 20%/80-100%                                            Molecular weight  20,000-30,000                                                pH                8-12                                                         Density           liquid products: 1.1 g/cm.sup.3                                                solid products: 1.7-1.9 g/cm.sup.3                           __________________________________________________________________________

The mixtures described below of the abovementioned individual components were prepared by simply mixing the components in the relative amounts given. In each case, pbw is parts by weight.

    ______________________________________                                                            Viscosity of the                                                               combination described,                                                         measured as an X%                                                              aqueous solution mPa · s                           ______________________________________                                          1  1 pbw     of methylhydroxy-                                                                              30,500                                                         ethylcellulose (1)                                                                            (as 1.3% aqueous                                      +0.15 pbw of superabsorbent (1)                                                                         solution)                                             +0.15 pbw of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               2  1.7 pbw   of methylhydroxy-                                                                             145,000                                                         ethylcellulose (2)                                                                            (as 2% aqueous                                        +0.21 pbw of superabsorbent (2)                                                                         solution)                                             +0.009 pbw                                                                               of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               3  1.4 pbw   of methylhydroxy-                                                                             109,000                                                         ethylcellulose (3)                                                                            (as 2% aqueous                                        +0.40 pbw of superabsorbent (1)                                                                         solution)                                             +0.20 pbw of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               4  1.6 pbw   of methylhydroxy-                                                                              88,000                                                         ethylcellulose (4)                                                                            (as 2% aqueous                                        +0.2 pbw  of superabsorbent (1)                                                                         (solution)                                            +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               5  1.6 pbw   of methylhydroxy-                                                                             102,000                                                         ethylcellulose (5)                                                                            (as 2% aqueous                                        +0.3 pbw  of superabsorbent (2)                                                                         solution)                                             +0.1 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               6  1.8 pbw   of methylhydroxy-                                                                              73,,000                                                        ethylcellulose (6)                                                                            (as 2% aqueous                                        +0.2 pbw  of superabsorbent (1)                                                                         solution)                                          7  0.5 pbw   of methylhydroxy-                                                                              27,500                                                         ethylcellulose (7)                                                                            (as 1% aqueous                                        +0.5 pbw  of superabsorbent (1)                                                                         solution)                                          8  1.4 pbw   of hydroxyethyl-                                                                               89,500                                                         cellulose      (as 2% aqueous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                               9  1.8 pbw   of hydroxyethyl-                                                                               30,000                                                         cellulose      (as 2% aqeuous                                        +0.2 pbw  of superabsorbent (1)                                                                         solution)                                         10  1.6 pbw   of hydroxyethyl-                                                                               48,000                                                         cellulose      (as 2% aqueous                                        +0.2 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              11  1.4 pbw   of carboxymethyl-                                                                              7,500                                                          hydroxyethylcellulose                                                                         (as 2% aqueous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              12  1.7 pbw   of xanthan gum  14,500                                               +0.3 pbw  of superabsorbent (1)                                                                         (as 2% aqueous                                                                 solution)                                         13  1.4 pbw   of xanthan gum  18,200                                               +0.4 pbw  of superabsorbent (1)                                                                         (as 2% aqueous                                        0.2 pbw   of naphthalene-                                                                               solution)                                                       sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              14  1.4 pbw   of methylhydroxy-                                                                              51,000                                                         propylcellulose                                                                               (as 2% aqueous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                               solution)                                                       sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              15  1.4 pbw   of ethylhydroxyethyl-                                                                          43,000                                                         cellulose      (as 2% aqueous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              16  1.7 pbw   of alkoxyhydroxy-                                                                              78,000                                                         propylhydroxyethyl-                                                                           (as 2% aqueous                                                  cellulose (1)  solution)                                             +0.3 pbw  superabsorbent                                                   17  1.7 pbw   of alkoxyhydroxy-                                                                              80,000                                                         propylhydroxyethyl-                                                                           (as 2% aqueous                                                  cellulose      solution)                                             +0.2 pbw  superabsorbent (1)                                                                            solution)                                             +0.1 pbw  naphthalenesulfonic-                                                           acid/formaldehyde                                                              condensation product                                                           sodium salt                                                      18  1.2 pbw   of methylhydroxy-                                                                             450,000                                                         ethylcellulose (8)                                                                            (as 2% aqeuous                                        +0.8 pbw  of superabsorbent (3)                                                                         solution)                                         19  1.7 pbw   of hydroxypropyl-                                                                              13,500                                                         starch (crosslinked                                                                           (as 2% aqueous                                                  with epichlorohydrin)                                                                         solution)                                             0.3 pbw   of superabsorbent (1)                                            20  1.7 pbw   of guar gum (guar                                                                              94,000                                                         endosperm flour)                                                                              (as 2% aqueous                                        + 0.3 pbw of superabsorbent (3)                                                                         solution)                                         21  1.7 pbw   of hydroxypropylguar                                                                           61,000                                               +0.3 pbw  of superabsorbent (3)                                                                         (as 2% aqeuous                                                                 solution)                                         22  1.7 pbw   of carboxymethyl-                                                                              44,,000                                                        hydroxypropylguar                                                                             (as 2% aqueous                                        0.3 pbw   of superabsorbent (3)                                                                         solution)                                         23  1.7 pbw   of hydroxypropylguar                                                                           45,000                                               0.2 pbw   of superabsorbent (3)                                                                         (as 2% aqeuous                                        +0.1 pbw  of naphthalene-                                                                               solution)                                                       sulfonic acid/formal-                                                          dehyde condensation                                                            product sodium salt                                              24  1.7 pbw   of guar gum, quater-                                                                          strong gelling, not                                             nary-substituted                                                                              measurable, aqueous                                   +0.3 pbw  of superabsorbent (3)                                                                         solution)                                         25  1.4 pbw   of methylhydroxy-                                                                              73,000                                                         ethylcellulose (3)                                                                            (as 2% aqueous                                        +0.4 pbw  of superabsorbent (3)                                                                         solution)                                             +0.2 pbw  melamine/formaldehyde                                                          condensation product,                                                          sulfonated, sodium                                                             salt                                                             26  1.4 pbw   of hydroxyethyl-                                                                               32,000                                                         cellulose      (as 2% aqeuous                                        +0.4 pbw  of superabsorbent (3)                                                                         solution)                                             +0.2 pbw  of melamine/formal-                                                            dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      27  1.4 pbw   of carboxymethyl-                                                                              4,500                                                          hydroxyethylcellulose                                                                         (as 2% aqueous                                        +0.4 pbw  of superabsorbent (2)                                                                         solution)                                             +0.2 pbw  of melamine/formal-                                                            dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      28  1.4 pbw   of methylhydroxy-                                                                              39,000                                                         propylcellulose                                                                               (as 2% aqeuous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of melamine/formal-                                                            dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      29  1.4 pbw   of ethylhydroxyethyl-                                                                          14,300                                                         cellulose      (as 2% aqueous                                        +0.4 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of melamine/formal-                                                            dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      30  1.0 pbw   of xanthan gum  15,700                                               +0.4 pbw  of superabsorbent (1)                                                                         (as 2% aqueous                                        +0.2 pbw  of melamine/formal-                                                                           solution)                                                       dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      31  1.0 pbw   of hydroxypropyl-                                                                               7,400                                                         starch         (as 2% aqueous                                        +0.8 pbw  of superabsorbent (1)                                                                         solution)                                             +0.2 pbw  of melamine/formal-                                                            dehyde condensation                                                            product, sulfonated,                                                           sodium salt                                                      32  1.4 pbw   of methylhydroxyethyl                                                                         102,000                                                         cellulose (9)  (as 2% aqeuous                                        +0.4 pbw  of superabsorbent (3)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product, calcium salt                                            33  1.4 pbw   of hydroxyethyl-                                                                               63,500                                                         cellulose      (as 2% aqueous                                        +0.4 pbw  of superabsorbent (3)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product, calcium salt                                            34  1.4 pbw   of guar gum (guar                                                                              70,000                                                         endosperm flour)                                                                              (as 2% aqueous                                        +0.4 pbw  of superabsorbent (3)                                                                         solution)                                             +0.2 pbw  of naphthalene-                                                                sulfonic acid/formal-                                                          dehyde condensation                                                            product, calcium salt                                            35  1.4 pbw   of hydroxypropyl guar                                                                          55,800                                               +0.4 pbw  of superabsorbent (3)                                                                         (as 2% aqueous                                        +0.2 pbw  of naphthalene-                                                                               solution)                                                       sulfonic acid/formal-                                                          dehyde condensation                                                            product, calcium salt                                            36  1.4 pbw   of xanthan gum  14,600                                               +0.4 pbw  of superabsorbent (3)                                                                         (as 2% aqueous                                        +0.2 pbw  of naphthalene-                                                                               solution)                                                       sulfonic acid/formal-                                                          dehyde condensation                                                            product, calcium salt                                            ______________________________________                                    

    __________________________________________________________________________     Viscosity measurements of superabsorbent in water or superabsorbent +          polycondensation products without use of derivatives of natural polymers                   a    b    c   d    e    f   g    h    i   j    k                               ppw  ppw  ppw ppw  ppw  ppw ppw  ppw  ppw ppw  ppw                 __________________________________________________________________________     Superabsorbent (1)                                                                         0.2  0.2  0.2 0.4  0.4  0.4 0.6  0.6  0.6 0.4  0.4                 Naphthalenesulfonic                                                                        --   0.2  --  --   0.2  0.4 --   0.2  --  0.1  --                  acid/formaldehyde                                                              polycondensation                                                               product, sodium                                                                salt or calcium salt                                                           Melamine/formal-                                                                           --   --   0.2 --   --   0.2 --   --   0.2 --   0.1                 dehyde polycondensa-                                                           tion product, sulfon-                                                          ated, sodium salt                                                              Water       99.8 99.6 99.6                                                                               99.6 99.4 99.4                                                                               99.4 99.2 99.2                                                                               99.5 99.5                Viscosity measured                                                                         3200 60   55  12000                                                                               200  185 20000                                                                               4000 4000                                                                               1500 1400                using Brookfield RV                                                            20 rpm, 25° C. RT                                                       Notes on appearance                                                                        gel-like                                                                            yellow-                                                                             clear,                                                                             gel-like                                                                            yellow-                                                                             clear,                                                                             gel-like                                                                            yellow-                                                                             clear,                                                                             yellow-                                                                             clear               of samples: material                                                                            ish, clear,                                                                         color-                                                                             material                                                                            ish, clear,                                                                         color-                                                                             material                                                                            ish, clear                                                                          color-                                                                             ish,                                                                                color-                          non-flow-                                                                           flow-                                                                               less                                                                               non-flow-                                                                           flow-                                                                               less                                                                               non-flow- less                                                                               flow-                                                                               less,                           able able flow-                                                                              able able flow-                                                                              able          able flow-                                     able          able                   able                __________________________________________________________________________

    __________________________________________________________________________     Results of the viscosity masurements (Brookfield RV, 20 rpm, 25°        C. Rt)                                                                                                            Viscosity of                                                        Viscosity of methyl-                                                                      combination described,                                              hydroxyethylcellulose                                                                     measured as                                                         as 1% aqueous                                                                             X% aqueous                                  No.                                                                               Combinations, comprising:                                                                           solution mPa · s                                                                 solution mPa · s                   __________________________________________________________________________     a  1.7 pbw                                                                              of methylhydroxyethylcellulose                                                                --         29,300 mPa · s                                                        (as 1% aqueous solution)                       +0.3 pbw                                                                             of superabsorbent (1)                                                 b  1.7 pbw                                                                              of methylhydroxyethylcellulose                                                                --         26,000 mPa · s                        +0.2 pbw                                                                             of superabsorbent (1)     (as 1% aqueous solution)                       +0.2 pbw                                                                             of naphthalenesulfonic acid/                                                   formaldehyde condensation                                                      product sodium salt                                                   c        methylhydroxyethylcellulose                                                                   2,400      --                                                   without additives                                                     __________________________________________________________________________

    ______________________________________                                         1. Paste-like tile adhesive                                                                  a                                                                              (com-                                                                          parative                                                                       sample)                                                                               b       c       d                                         ______________________________________                                         Components      pbw      pbw     pbw   pbw                                     Filler mixture comprising                                                                      67       67      67    67                                      finely ground calcium                                                          carbonate and ground mica                                                      Bentonite       1        1       1     0.8                                     Hydroxyethylcellulose,                                                                         0.68     0.4     0.30  0.30                                    viscosity level 100,000                                                        mPa · s (2% aqeuous                                                   solution)                                                                      Superabsorbent (1)                                                                             --       0.2     0.25  0.30                                    Polycondensation product                                                                       --       --      0.05  --                                      based on naphthalene-                                                          sulfonic acid/formaldehyde                                                     alkali metal salt                                                              Water           20-25    20-25   20-25 20-25                                   Plastic dispersion                                                                             10       10      10    10                                      (based on styrene/                                                             acrylate)                                                                      Antifoam        0.1      0.1     0.1   0.1                                     Preservative    0.15     0.15    0.15  0.15                                    Aminomethylpropanol (as                                                                        0.1      0.1     0.1   0.1                                     alkalising agent)                                                              Antisliding behavior of                                                                        2-3      1-2     2-3   0                                       stonework tiles (10 × 10 cm)                                             on concrete (mm)                                                               Skinning time (min)                                                            tested with stonework                                                          tiles (5 × 5 cm) on concrete                                             Tiles loaded with 1 kg                                                                         20       25      25-30 20-25                                   Tiles loaded with 2 kg                                                                         30       35      35-40 30-35                                   ______________________________________                                    

    ______________________________________                                         2. Ready-mixed jointing compound                                                             a     b       c       d                                          ______________________________________                                         Filler mixture (finely                                                                         58      58      58    58                                       ground calcium carbonate                                                       0-20 μm)                                                                    Finely ground mica                                                                             4       4       4     4                                        Attapulgite, finely ground                                                                     2.5     --      2.5   --                                       (as inorganic thickener)                                                       Methylhydroxyethyl-                                                                            0.50    0.25    0.40  0.30                                     cellulose or methyl-                                                           hydroxypropylcellulose visc.                                                   level 15000-60000 mPa · s                                             (2% aqueous solution)                                                          Hydroxyethylcellulose                                                                          --      --      0.10  --                                       visc. level 15000-60000                                                        mPa · s (2% aqueous                                                   solution)                                                                      Superabsorbent (1)                                                                             --      0.25    --    0.20                                     Water           30-35   30-35   30-35 30-35                                    Plastic dispersion (con-                                                                       4-6     4-6     4-6   4-6                                      taining polyvinyl acetate                                                      plasticized with 10% of                                                        dibutyl phthalate                                                              Antifoam        0.1     0.1     0.1   0.1                                      Preservative    0.1     0.1     0.1   0.1                                      Propylene glycol                                                                               1.0     1.0     1.0   1.0                                      Consistency of the com-                                                                        some-   easily  more  easily                                   pound and processability                                                                       what    proc-   easily                                                                               proc-                                                    viscous essable proc- cessable,                                                and     no      essable                                                                              a,no                                                     tacky,  after-  than  after-                                                   exten-  thick-  less  thick-                                                   sive    ening   tacky,                                                                               ening                                                    after-  of the  exten-                                                                               of the                                                   thick-  paste-  sive  paste-                                                   ening   like    after-                                                                               like                                                             mate-   thick-                                                                               mate-                                                            rial    ening rial                                                                     of the                                                                         paste-                                                                         like                                                                           mate-                                                                          ial                                            Shrinkage behavior of                                                                          exten-  re-     exten-                                                                               no                                       the hardened material on                                                                       sive    duced   sive  shrink                                   gypsum-board sheeting                                                                          shrink- shrink- shrink-                                                                              age,                                                     age,    age,    age,  hardly                                                   crack-  hardly  too   any                                                      ing in  any     many  crack-                                                   the     cracks  cracks                                                                               ing                                                      hard-           in the                                                                               in the                                                   ened            hard- hard-                                                    mate-           ened  ened                                                     rial            mate- mate-                                                                    rial  rial                                     ______________________________________                                    

    ______________________________________                                         3. Pulverulent jointing compound (without addition of gypsum)                               a     b        c        d                                         ______________________________________                                         Filler mixture (compris-                                                                      92-94   92-94    92-94  92-94                                   ing finely ground calcium                                                      carbonate, mica, talc)                                                         Bentonites     0.6-1   0.6-1    0.5    --                                      Plastic dispersion powder                                                                     3-6     3-6      3-6    3-6                                     (copolymer of vinyl                                                            acetate/ethylene or                                                            versatic ester)                                                                Polyvinyl alcohol (low-                                                                       0.4-0.8 0.4-0.8  0.4-0.8                                                                               0.4-0.8                                 molecular-weight)                                                              Methylhydroxyethyl-                                                                           0.60    0.24     0.20   0.35                                    cellulose or methyl-                                                           hydroxypropylcellulose                                                         visc. level 10000-100000                                                       mPa · s (2% aqueous                                                   solution)                                                                      Carboxymethylhydroxy-                                                                         --      0.30     0.30   --                                      ethylcellulose visc. level                                                     3000-10000 mPa · s                                                    (2% aqueous solution)                                                          Superabsorbent (1)                                                                            --      0.06     0.1    0.25                                    Addition of water per                                                                         45-50   45-50    45-50  45-50                                   100 g of pulverulent                                                           mixture                                                                        Consistency and process-                                                                      good,   good,    very   very                                    ability of the compound                                                                       slight  slight   good   good,                                   mixed with water                                                                              struc-  improve- dis-   good                                                   turing  ment     tinct  struc-                                                         in the   improve-                                                                              ture                                                           struc-   ment   and                                                            ture     in the stabil-                                                                 struc- ity                                                                     ture                                                                           of the                                                                         com-                                                                           pound                                          Stability of consistency                                                                      gradu-  hardly   no     no                                      of the compound mixed                                                                         ally    any      after  after                                   with water     after   after    thick- thick-                                                 thick-  thick-   ening  ening                                                  ening   ening                                                                  (after                                                                         7 days)                                                         Shrinkage behavior and                                                                        exten-  less     hardly hardly                                  cracking on gypsum-board                                                                      sive    crack-   any    any                                     sheeting       crack-  ing      shrink-                                                                               shrink-                                                ing              age    age                                                                     hardly no                                                                      any    crack-                                                                  crack- ing                                                                     ing                                            ______________________________________                                    

The use of the polycondensation products in the combinations described of derivatives of natural polymers with superabsorbents leads to transparent, predominantly still pourable polymer solutions. Particularly advantageous are additions of melamine/formaldehyde condensation products, resulting in completely transparent and colorless solutions.

Solutions of natural polymers show in many cases naturally more or less extensive clouding, which is removed by addition of superabsorbents and melamine/formaldehyde condensation products. This optical effect represents an improvement in the quality of natural polymers in those applications in which solubility of the polymers in water with the formation of a transparent solution is necessary. 

We claim:
 1. A mixture consisting essentially of the following componentsa) at least 10% by weight of1) water-soluble natural polymer or 2) a derivative of said water-soluble natural polymer selected from the group consisting of cellulose ethers, starch ethers, carboxymethyl guar, hydroxypropyl guar, carboxymethyl hydroxypropyl guar, and cationized guar. b. 1 to 89% by weight of an alkali mend salt or ammonium salt of a crosslinked polyacrylate which polyacrylate is optionally grafted with a starch, and c. 5 to 60% by weight of a water-soluble alkali metal salt or alkaline earth metal salt of an arylsulfonic acid/formaldehyde condensation product or of a sulfo-modified melamine/formaldehyde polycondensation product; said mixture is used in a building product.
 2. The mixture as claimed in claim 1, wherein the amount of said component (a) in said mixture is 10 to 90% by weight.
 3. The mixture as claimed in claim 1, wherein said polyacrylate is grafted with a starch.
 4. A building material product as claimed in claim 1, wherein said component (a) consists essentially of a starch ether, cellulose ether, or guar gum.
 5. The mixture as claimed in claim 1, wherein said mixture comprises 40 to 90% by weight of said component (a), 5 to 60% by weight of said component (b), and 5 to 40% by weight of said component (c).
 6. The mixture as claimed in claim 1, wherein said product can be formulated as a dry composition, and wherein said product contains 0.01 to 2% by weight, relative to the dry composition, of said mixture.
 7. A building material product as claimed in claim 6, wherein said product contains 0.1 to 0.5% by weight, relative to the dry composition, of said mixture.
 8. The mixture as claimed in claim 6, which has been blended with water.
 9. The mixture as claimed in claim 5, wherein component (b) is present in an amount from 10 to 60% by weight.
 10. The mixture as claimed in claim 9, wherein component (c) is present in an amount from 10 to 40% by weight.
 11. A building material as claimed in claim 10, wherein component (b) is present from 20 to 60% by weight.
 12. A mixture consisting of the following components:a) at least 10% by weight of1) a water-soluble natural polymer or 2) a derivative of said water-soluble natural polymer selected from the group consisting of cellulose ethers, starch ethers, carboxymethyl guar, hydroxypropyl guar, carboxymethyl hydroxypropyl guar, and cationized guar. b) 1 to 89% by weight of an alkali metal salt or ammonium salt of a crosslinked polyacrylate which polyacrylate is optionally grafted with a starch, and c) 5 to 60% by weight of a water-soluble alkali metal salt or alkaline earth metal salt of an arylsulfonic acid/formaldehyde condensation product or of a sulfo-modified melamine/formaldehyde polycondensation product: said mixture is to be used in a building product.
 13. The mixture as claimed in claim 12, wherein said component consists of 40 to 90% by weight of component a), 20 to 60% by weight of component b) and 10 to 40% by weight of component c).
 14. A mixture as claimed in claim 1, wherein said component (a) is selected from the group consisting of cellulose ethers, starch ethers, guar gum, xanthangum, carobseed flower, alginates and mixtures thereof. 